CSP backlight source

Abstract

The utility model relates to the technical field of backlight of display equipment, and provides a CSP backlight source. The CSP backlight comprises: a substrate comprising a light emitting circuit; the light-emitting packaging part is arranged on the substrate, electrically connected with the light-emitting circuit and comprises a blue light chip, a light nano material layer and a red-green-fluorescence conversion layer which are sequentially stacked from bottom to top, the light nano material layer at least covers the light-emitting front face of the blue light chip, and the red-green-fluorescence conversion layer at least covers the light nano material layer; the light-emitting packaging piece is used for converting and mixing light emitted by the blue light chip so as to emit white light, and the light-emitting packaging piece is manufactured through a chip scale package (CSP) technology; and the lens layer covers the light-emitting packaging piece in a gapless manner.

Description

Technical Field

[0001] This disclosure relates to the field of display device backlight technology, and more particularly to a CSP backlight. Background Technology

[0002] Currently, LED display solutions typically use blue light-emitting chips to excite quantum dots or phosphors to achieve white backlighting.

[0003] When using a blue light-emitting chip to excite phosphors to achieve white backlight, the white backlight performs poorly in the long wavelength range. When the color mixing effect of the matching color filter is poor, the color purity of the light formed through the panel is not high enough, and there are differences in color reproduction. Utility Model Content

[0004] In view of this, the present disclosure provides a CSP backlight to solve the technical problem of insufficient color purity of white backlight in the prior art.

[0005] To achieve the above objectives, the technical solution adopted in this disclosure is:

[0006] This disclosure provides a CSP backlight, which includes: a substrate including a light-emitting circuit; a light-emitting package disposed on the substrate and electrically connected to the light-emitting circuit, comprising a blue light chip, a light nanomaterial layer, and a red-green fluorescence conversion layer stacked sequentially from bottom to top, wherein the light nanomaterial layer covers at least the front side of the blue light chip, and the red-green fluorescence conversion layer covers at least above the light nanomaterial layer, for converting and mixing the light emitted by the blue light chip to emit white light, and the light-emitting package is fabricated using chip-scale packaging (CSP) technology; and a lens layer that covers the light-emitting package without gaps.

[0007] In one embodiment, the blue light chip is a MiniLED blue light chip.

[0008] In one embodiment, the red-green fluorescence conversion layer includes a red fluorescence conversion layer and a green fluorescence conversion layer stacked together, or the red-green fluorescence conversion layer includes a mixed fluorescence conversion layer containing red phosphor and green phosphor.

[0009] In one embodiment, the lens layer includes a diffusion layer, a reflection layer, and a lens arranged sequentially from bottom to top.

[0010] In one embodiment, the diffusion layer is a white glue layer or a silicone layer containing diffusion powder; and / or, the reflective layer is a white glue layer or a silicone layer containing diffusion powder.

[0011] In one embodiment, the diffusion powder comprises silicon dioxide, titanium dioxide, or solid particles of a mixture of silicon dioxide and titanium dioxide.

[0012] In one embodiment, the CSP backlight further includes an optical diaphragm assembly disposed in the light emission direction of the light-emitting package.

[0013] In one embodiment, the interface between the light-emitting package and the diffusion layer is a plane, while the interface between the diffusion layer and the reflective layer, as well as the interface between the reflective layer and the lens, are curved surfaces, with the curved surfaces protruding away from the blue light chip.

[0014] In one embodiment, the excitation wavelength of the blue light chip is 440nm to 470nm.

[0015] In one embodiment, the red-green phosphor conversion layer includes any one of the following: a nitride phosphor layer, a fluoride phosphor layer, and a silicate phosphor layer.

[0016] The beneficial effects of this disclosed embodiment compared with the prior art include: by covering the light-emitting front side of the blue light chip with a layer of light nanomaterials, stray light emitted by the blue light chip can be absorbed, resulting in higher purity of blue light, thereby improving the color purity and color reproduction of the obtained white backlight. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a CSP backlight provided in an embodiment of this disclosure;

[0019] Figure 2 This is a schematic diagram of another CSP backlight provided in an embodiment of this disclosure;

[0020] Figure 3 This is a schematic diagram of yet another CSP backlight provided in an embodiment of this disclosure;

[0021] Figure 4 This is a schematic diagram of another CSP backlight provided in the embodiments of this disclosure. Detailed Implementation

[0022] To make the technical problems, technical solutions, and beneficial effects to be solved by this disclosure clearer, the disclosure will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining this disclosure and are not intended to limit this disclosure.

[0023] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it may be directly or indirectly located on that other component. When a component is referred to as "connected to" another component, it may be directly or indirectly connected to that other component. The terms "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate orientations or positions based on the accompanying drawings, and are for ease of description only, and should not be construed as limiting the technical solution. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. "A plurality" means two or more, unless otherwise explicitly defined.

[0024] The CSP backlight according to embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. For ease of structural description, the following description uses a front-emitting backlight as an example, with the front side being the emission direction.

[0025] Figure 1 This is a schematic diagram of a CSP backlight provided in an embodiment of this disclosure; Figure 2 This is a schematic diagram of another CSP backlight provided in an embodiment of this disclosure; Figure 3 This is a schematic diagram of yet another CSP backlight provided in this embodiment of the present disclosure. Figure 4 This is a schematic diagram of another CSP backlight provided in the embodiments of this disclosure. The following is in conjunction with... Figures 1 to 4 Let's describe the CSP backlight provided in the embodiments of this disclosure.

[0026] like Figures 1 to 3 As shown, the CSP backlight provided in this embodiment includes a substrate, a light-emitting package, and a lens layer. The light-emitting package is electrically connected to the circuit layer of the substrate and includes a blue LED chip, a photonic nanomaterial layer, and a red-green fluorescence conversion layer stacked sequentially from bottom to top. The photonic nanomaterial layer covers at least the front side of the blue LED chip, and the red-green fluorescence conversion layer covers at least above the photonic nanomaterial layer. The blue LED chip is a blue light-emitting chip. The photonic nanomaterial consists of microparticles with a diameter of approximately 1 nm, which can absorb stray light in the blue light emitted by the blue LED chip, significantly improving the purity of the color light. The sequential stacking from bottom to top means that the photonic nanomaterial is stacked in front of the blue LED chip, and the red-green fluorescence conversion layer is stacked in front of the photonic nanomaterial.

[0027] Specifically, the substrate includes a circuit layer, which includes a light-emitting circuit. A light-emitting package is electrically connected to the light-emitting circuit. The electrodes of the blue LED chip are soldered to the light-emitting circuit on the substrate, thus positioning the blue LED chip on the front surface of the substrate. The front surface of the blue LED chip is the primary light-emitting surface; therefore, it is defined as the front light-emitting side, and the surrounding sides of the blue LED chip are the light-emitting sides. The light-emitting package is disposed on the front surface of the substrate and electrically connected to the circuit layer. The light-emitting package can be soldered onto the substrate using a COB (Chip-On-Board) flip-chip process. The light-emitting package emits white light in the light-emitting direction. A lens layer is seamlessly covered on the light-emitting package, and the lens layer and the light-emitting package are seamlessly bonded, ensuring that each light-emitting package has a sufficient light-emitting angle.

[0028] like Figure 1 As shown in the figure, a CSP backlight provided in this embodiment includes: a substrate 110, including a circuit layer; a light-emitting package disposed on the substrate and electrically connected to the light-emitting circuit on the circuit layer, including a blue light chip 121, a light nanomaterial layer 122, and a red-green fluorescence conversion layer 123 stacked from bottom to top, the light nanomaterial layer covering the front light-emitting side of the blue light chip but not covering the sides of the blue light chip, the red-green fluorescence conversion layer covering the top surface of the light nanomaterial layer and covering the sides of the blue light chip. The red-green fluorescence conversion layer is used to convert and mix the light emitted by the blue light chip to emit white light. The light-emitting package is fabricated using chip-scale packaging (CSP) technology; and a lens layer 130, which covers the light-emitting package without gaps. In this embodiment, the light-emitting package can be single-sided light-emitting, which generally means that the front light-emitting side of the blue light chip can emit light, while the surrounding sides of the blue light chip do not emit light. In this embodiment, a high color gamut white light-emitting package can be fabricated using CSP technology by employing a blue light chip 121, a photonic nanomaterial layer 122, and a red-green phosphor conversion layer 123. In the light-emitting package, the light emitted by the blue light chip 121 is absorbed by the photonic nanomaterial layer, then converted by the red-green phosphor conversion layer and mixed with the blue light to form white light. This direct-packaged light-emitting package offers high cost-effectiveness. Specifically, the blue light emitted by the blue light chip is absorbed by the photonic nanomaterial layer and then irradiates the red-green phosphor conversion layer, where it is converted into red and green light, which are then mixed with the blue light to form white light.

[0029] In this embodiment, the red-green fluorescence conversion layer can be a red fluorescence conversion layer and a green fluorescence conversion layer stacked together, or it can be a mixed fluorescence conversion layer containing red phosphor and green phosphor. When the red-green fluorescence conversion layer is a red fluorescence conversion layer and a green fluorescence conversion layer stacked together, the positions of the red fluorescence conversion layer and the green fluorescence conversion layer can be interchanged.

[0030] When the red-green fluorescent conversion layer consists of a stacked red fluorescent conversion layer and a green fluorescent conversion layer, the blue light emitted by the blue light chip is absorbed by the light nanomaterial layer and then irradiates the red fluorescent conversion layer and the green fluorescent conversion layer, respectively, and can be converted into red light and green light. After mixing with the blue light, they form white light, thus enabling the light-emitting package to emit white light.

[0031] When the red-green phosphor conversion layer is a mixed phosphor conversion layer containing red and green phosphors, the blue light emitted by the blue light chip is absorbed by the light nanomaterial layer and then irradiates the mixed phosphor conversion layer, which can convert the mixed light of red and green light into white light. This white light is then mixed with the blue light to form white light, thus enabling the light-emitting package to emit white light.

[0032] In the technical solution of this embodiment, a light nanomaterial layer is provided on the front side of the blue light chip. The light nanomaterial layer can absorb stray light in the blue light, and then obtain white light through the red-green fluorescent conversion layer. Since the stray light is absorbed, the color purity of the light is higher and the color reproduction is better.

[0033] like Figure 2 As shown, another CSP backlight provided in this embodiment includes: a substrate 210, including a circuit layer; a light-emitting package disposed on the substrate and electrically connected to the light-emitting circuit on the circuit layer, including a blue light chip 221, a light nanomaterial layer 222, and a red-green fluorescence conversion layer 223 stacked sequentially from bottom to top. The light nanomaterial layer covers the front light-emitting side of the blue light chip and the side of the blue light chip, and the red-green fluorescence conversion layer covers the top surface and the side surface of the light nanomaterial layer. The side surface of the blue light chip refers to the surrounding side surface of the blue light chip. The top surface of the light nanomaterial layer refers to the front surface of the light nanomaterial layer, and the side surface of the light nanomaterial layer refers to the surrounding side surface of the light nanomaterial layer. The red-green fluorescence conversion layer is used to convert and mix the light emitted by the blue light chip to emit white light. The light-emitting package is fabricated using chip-scale packaging (CSP) technology; and a lens layer 230, which covers the light-emitting package without gaps. In this embodiment, the light-emitting package can emit light from five sides, meaning that the four light-emitting side surfaces and one light-emitting front surface of the blue light chip can all emit light.

[0034] In this embodiment of the disclosure, when the red-green fluorescent conversion layer is a red fluorescent conversion layer and a green fluorescent conversion layer stacked together, the blue light emitted by the blue light chip is absorbed by the light nanomaterial layer and then irradiates the red fluorescent conversion layer and the green fluorescent conversion layer, which can be converted into red light and green light respectively. After mixing with the blue light, they form white light, thereby making the light-emitting package emit white light.

[0035] When the red-green phosphor conversion layer is a mixed phosphor conversion layer containing red and green phosphors, the blue light emitted by the blue light chip is absorbed by the light nanomaterial layer and then irradiates the mixed phosphor conversion layer, which can convert the mixed light of red and green light into white light. This white light is then mixed with the blue light to form white light, thus enabling the light-emitting package to emit white light.

[0036] In the technical solution of this disclosure embodiment, a light nanomaterial layer is provided on the front and side of the blue light chip. The light nanomaterial layer can absorb stray light in the blue light, and then obtain white light through the red-green fluorescent conversion layer. Since the stray light is absorbed, the color purity of the light is higher and the color reproduction is better.

[0037] like Figure 3 As shown, another CSP backlight provided in this embodiment includes: a substrate 310, including a circuit layer; a light-emitting package disposed on the substrate and electrically connected to the light-emitting circuit on the circuit layer, including a blue LED chip 321, a photonanomaterial layer 322, and a red-green fluorescence conversion layer 323 stacked sequentially from bottom to top. The photonanomaterial layer covers the front light-emitting side of the blue LED chip but does not cover the sides of the blue LED chip, and the red-green fluorescence conversion layer covers the top surface of the photonanomaterial layer but does not cover the sides of the blue LED chip. The red-green fluorescence conversion layer is used to convert and mix the light emitted by the blue LED chip to emit white light. The light-emitting package is fabricated using chip-level packaging (CSP) technology; and a lens layer 330, which covers the light-emitting package without gaps. In this embodiment, the light-emitting package can be single-sided, that is, the front light-emitting side of the blue LED chip can emit light, while the surrounding sides of the blue LED chip do not emit light. In this embodiment, the sides of the blue LED chip can be encapsulated with encapsulating adhesive.

[0038] In this embodiment of the disclosure, when the red-green fluorescent conversion layer is a red fluorescent conversion layer and a green fluorescent conversion layer stacked together, the blue light emitted by the blue light chip is absorbed by the light nanomaterial layer and then irradiates the red fluorescent conversion layer and the green fluorescent conversion layer, which can be converted into red light and green light respectively. After mixing with the blue light, they form white light, thereby making the light-emitting package emit white light.

[0039] When the red-green phosphor conversion layer is a mixed phosphor conversion layer containing red and green phosphors, the blue light emitted by the blue light chip is absorbed by the light nanomaterial layer and then irradiates the mixed phosphor conversion layer, which can convert the mixed light of red and green light into white light. This white light is then mixed with the blue light to form white light, thus enabling the light-emitting package to emit white light.

[0040] In the technical solution of this embodiment, a light nanomaterial layer is provided on the front side of the blue light chip. The light nanomaterial layer can absorb stray light in the blue light, and then obtain white light through the red-green fluorescent conversion layer. Since the stray light is absorbed, the color purity of the light is higher and the color reproduction is better.

[0041] In this embodiment, the blue light chip can be a MiniLED blue light chip. MiniLED refers to an LED chip with a size on the order of 100μm. The light-emitting package emits white light, and since the light-emitting chip is a MiniLED, a high color gamut white light MiniCOB package is formed. Preferably, the blue light chip is generally circular or square, and its excitation wavelength is 440nm to 470nm.

[0042] In the embodiments of this disclosure, the red-green fluorescence conversion layer can be a nitride phosphor layer, a fluoride phosphor layer, and a silicate phosphor layer composed of nitride phosphor, fluoride phosphor, and silicate phosphor. Specifically, when the red-green fluorescence conversion layer is a mixed fluorescence conversion layer containing red and green phosphors, the red and green phosphors can be mixed in the encapsulating adhesive to form the mixed fluorescence conversion layer. When the red-green fluorescence conversion layer consists of a stacked red fluorescence conversion layer and a green fluorescence conversion layer, red phosphor can be mixed in the encapsulating adhesive to form a red fluorescence conversion layer, and green phosphor can be mixed in the encapsulating adhesive to form a green fluorescence conversion layer.

[0043] The red and green phosphors can be narrow-peak phosphors such as green β-sialon, and the red phosphor can be narrow-peak red phosphors such as KSF or QD, but are not limited to these. The blue light emitted by the blue chip is absorbed by the photonanomaterial layer, and then shines onto the red-green phosphor conversion layer, converting it into red and green light. This red and green light then mixes with the blue light to form white light, thus causing the light-emitting package to emit white light.

[0044] In this embodiment, the lens layer includes a diffusion layer, a reflective layer, and a lens arranged sequentially from bottom to top. The front surface of the lens layer is arc-shaped, and the light-emitting package is located in the middle of the arc-shaped lens layer. With the center of the light-emitting package as the optical center, covering the entire light-emitting package with the lens layer opens up the beam angle of the light-emitting package. The lens layer and the light-emitting package are integrated into one unit without gaps or cavities, forming an optical lens structure with a large emission angle. Opening up the emission angle of the light-emitting package allows for a larger coverage area, thereby reducing the number of Mini LEDs used within the same specifications.

[0045] Specifically, a diffusion layer, a reflective layer, and a lens are arranged sequentially from bottom to top: the diffusion layer is placed on the front side of the light-emitting package, the reflective layer is placed on the front side of the diffusion layer, and the lens is placed on the front side of the reflective layer.

[0046] In this embodiment, the diffusion layer can be a white adhesive layer or a silicone layer containing diffusion powder; the reflective layer can be a white adhesive layer or a silicone layer containing diffusion powder. The diffusion powder can be silicon dioxide, titanium dioxide, or solid particles of a mixture of silicon dioxide and titanium dioxide. The diffusion powder in this embodiment enhances the light diffusion of the lens, allowing the light emitted from the light source to be distributed more evenly, reducing glare and shadows. Furthermore, the diffusion powder can maintain high light transmittance while ensuring light diffusion, reducing light energy loss.

[0047] In this embodiment, the interface between the light-emitting package and the diffusion layer is a plane, while the interface between the diffusion layer and the reflective layer, as well as the interface between the reflective layer and the lens, are curved surfaces, with the curved surfaces protruding in a direction away from the blue light chip.

[0048] Specifically, when the front surface of the light-emitting package is flat, the interface between the light-emitting package and the diffusion layer is flat, and the rear surface of the diffusion layer is flat, the diffusion layer can cover the light-emitting package without gaps, ensuring that each light-emitting package has a sufficient emission angle. Similarly, when the front and rear surfaces of the lens are curved, and the interfaces between the reflective layer and the lens, and between the diffusion layer and the reflective layer, are also curved, the diffusion layer, reflective layer, and lens of the lens layer can sequentially cover the light-emitting package without gaps, ensuring that each light-emitting package has a sufficient emission angle.

[0049] like Figure 4As shown, the CSP backlight in this embodiment further includes an optical film assembly, which is disposed in the light emission direction of the light-emitting package. The optical film assembly includes a composite optical film 410 and a diffuser plate 420. The diffuser plate 420 is disposed in the light emission direction of the lens layer, and the composite optical film 410 is located in front of the diffuser plate 420. The optical film assembly can change the direction of light propagation and reflection; it can be single-layered or multi-layered and composed of different types of materials. Different effects can be achieved by changing different parameters such as materials, thickness, reflectivity, and transmittance.

[0050] Composite optical films are multifunctional optical film materials that assemble multiple different optical films into a single sheet using a composite process. While maintaining their optical performance, composite optical films can achieve overall thinning and cost reduction in display devices, and improve the yield and efficiency of backlight module assembly. A diffuser plate is a component used in optical systems, its main function being to diffuse or uniformly distribute light. Through surface frosting, dotting, prism, and other processing techniques, diffuser plates can uniformly diffuse light, reducing glare and bright spots, and improving the uniformity and softness of light. In backlight modules and other fields, diffuser plates are used to uniformly diffuse the light emitted by the backlight across the entire screen to improve light uniformity and softness. Diffuser plates are typically made of materials with high light transmittance and good diffusion properties, such as PS (polystyrene), PC (polycarbonate), and acrylic.

[0051] Based on the above CSP backlight, this disclosure embodiment can also provide a display device, which includes a display panel and the CSP backlight in the above technical solution.

[0052] According to the CSP backlight provided in the embodiments of this disclosure, by covering the light-emitting front side of the blue light chip with a layer of light nanomaterials, the stray light emitted by the blue light chip can be absorbed, making the purity of the blue light higher, thereby improving the color purity and color reproduction of the obtained white backlight.

[0053] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A CSP backlight, characterized by, The CSP backlight source comprises: a substrate comprising light-emitting circuitry; a light-emitting package disposed on the substrate and electrically connected to the light-emitting circuitry, comprising, from bottom to top, a blue light chip, a light nanomaterial layer, and a red-green fluorescent conversion layer, the light nanomaterial layer covering at least a light-emitting front surface of the blue light chip, and the red-green fluorescent conversion layer covering at least above the light nanomaterial layer, for converting and mixing light emitted by the blue light chip to emit white light, the light-emitting package being made by chip-scale packaging (CSP) technology; a lens layer covering the light-emitting package without gaps.

2. The CSP backlight of claim 1, wherein, The blue light chip is a MiniLED blue light chip.

3. The CSP backlight of claim 1, wherein, The red-green fluorescent conversion layer comprises a red fluorescent conversion layer and a green fluorescent conversion layer stacked together, or the red-green fluorescent conversion layer comprises a mixed fluorescent conversion layer mixed with red fluorescent powder and green fluorescent powder.

4. The CSP backlight of claim 1, wherein, The lens layer comprises, from bottom to top, a diffusion layer, a reflective layer, and a lens.

5. The CSP backlight of claim 4, wherein, The diffusion layer is a white glue layer or a silica gel layer containing diffusion powder; and / or the reflective layer is a white glue layer or a silica gel layer containing diffusion powder.

6. The CSP backlight of claim 1, wherein, The CSP backlight source further comprises an optical film assembly disposed in a light-emitting direction of the light-emitting package.

7. The CSP backlight of claim 4, wherein, An interface between the light-emitting package and the diffusion layer is a flat surface, and an interface between the diffusion layer and the reflective layer and an interface between the reflective layer and the lens are curved surfaces, which are convex in a direction away from the blue light chip.

8. The CSP backlight of claim 1, wherein, An excitation wavelength of the blue light chip is 440-470 nm.

9. The CSP backlight of claim 1, wherein, The red-green fluorescent conversion layer comprises any one of a nitride fluorescent powder layer, a fluoride fluorescent powder layer, and a silicate fluorescent powder layer.

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